At the beginning of the development of powder coatings […]
At the beginning of the development of powder coatings in China, due to lack of data, it is inevitable to be influenced by the experience of solvent-based coatings, inks and plastics industries when selecting pigments and color combinations. With the rapid development of the industry and the richness of relevant knowledge and information, powder coatings are becoming more and more targeted in selecting pigments, and the standards are getting higher and higher. If you do not understand the chemical composition and related properties of various pigments, face the hundreds. Thousands of pigment models will be at a loss, resulting in high color matching costs or failure to meet the requirements of use.
First, the color:
Color is the most basic performance of pigments. People use this to divide pigments into red, yellow and blue. The color of the pigment is mainly determined by the chemical structure and crystal form, and the particle size has an influence on the hue. When it comes to color, you should pay attention to the chroma or saturation problem, which is usually called vividness. Chroma is one of the attributes of color, indicating the degree to which the color deviates from the same gray. It depends on the selectivity of the pigment for light wave reflection. The higher the selectivity, the higher the chroma. The various monochromatic lights of visible light are the most chroma. In the actual color matching, the color with lower chroma can be used to match the lower chroma color, and vice versa. Some plates which are picked up with organic pigments cannot be recalled with any increase in the amount of inorganic pigments, which is due to the lower chroma of inorganic pigments. Some particularly bright inks or paint swatches, powder coatings cannot be recalled because of the lower pigment concentration in powder coatings, while the higher curing temperatures exclude many heat-labile, bright pigments.
Second, tinting strength:
Tinting strength, also known as tinting strength, is the ability of a pigment to impart color to a colored object. It mainly depends on the chemical structure and is also related to factors such as crystal form and particle size.
Third, heat resistance:
The heat resistance is mainly related to the chemical structure and crystal form, and is also related to the particle size, pigment surface treatment and other factors, and many of the pigments are diluted and the heat resistance is lowered.
Fourth, light resistance and weather resistance:
The light resistance reflects the degree of darkening and fading of the pigment under illumination, ranging from severe to slightly graded from 1 to 8, with grade 8 indicating the best lightfastness. Weatherability more fully reflects the fastness of pigments under outdoor natural conditions, from the worst to the best, divided into 1 to 5 grades. The light fastness and weather resistance of the pigment mainly depend on the chemical structure, and are also related to the crystal form, the particle size, and the surface treatment. Many of the pigments are diluted, and the light resistance and weather resistance are lowered.